Risk of adverse birth outcomes after adolescent and young adult cancer

Background Many women diagnosed with cancer as adolescents and young adults (AYAs, age 15-39 years) want biological children after cancer but lack information on the potential impact of their cancer history on future reproductive outcomes. We investigated the risk of adverse birth outcomes among AYA cancer survivors. Methods We identified insured women diagnosed with AYA breast cancer, thyroid cancer, gynecologic cancers, lymphoma, or melanoma from 2003 to 2016 in the state of North Carolina or the Kaiser Permanente health care systems in northern and southern California. Post-diagnosis births to cancer survivors were each matched with up to 5 births to women without cancer. Risk ratios for preterm birth (<37 completed weeks), very preterm birth (<34 completed weeks), low birth weight (<2500 g), and small for gestational age (SGA, <10th percentile of weight for gestational age) were estimated using modified Poisson regression. Results Analyses included 1648 births to 1268 AYA cancer survivors and 7879 births to 6066 women without cancer. Overall, risk of preterm birth, very preterm birth, low birth weight, and SGA did not significantly differ between births to women with and without cancer. However, births to women with gynecologic cancers had a significantly increased risk of low birth weight (risk ratio = 1.82; 95% confidence interval: 1.03 to 3.21) and suggested increased risk of preterm birth (risk ratio = 1.59; 95% confidence interval: 0.99 to 2.54). Chemotherapy exposure was not associated with increased risk of adverse birth outcomes. Conclusions Women with gynecologic cancers, but not other cancers, had an increased risk of adverse birth outcomes compared to women without cancer.